tbuckley/cabot-search huggingface dataset:
TMIC-64. CHARACTERIZATION OF THE TUMOR MICROENVIRONMENT IN DIFFUSE MIDLINE GLIOMAS (DMG) FOR 3D <i>IN VITRO</i> MODEL BUILDING
Authors: Sarah Kremer, Rhea John, Peng Jin, Sharon Michelhaugh, Jessica Cunningham, Samantha Howerton, Augustine Eze, Javad Nazarian, Jennifer Munson
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Diffuse midline glioma (DMG) is an aggressive pediatric brain cancer. Few comprehensive tumor characterization studies have been conducted due to the relative scarcity of tissue samples. However, it is well known that the surrounding microenvironment, and particularly the cells of the normal brain, influence tumor outcomes. Here, we investigate the cell type distribution among patient autopsy samples, comparing the primary tumor, metastatic tumors, and normal brain tissue. METHODS Patient samples (n=10) were obtained at Children’s National through a postmortem autopsy program. All patients were diagnosed with DMG between the ages of four and thirteen. Brain sections were embedded in paraffin, sectioned into 5 μm thick slices, and stained using fluorescent immunohistochemistry. Targets included astrocytes (ALDH1L1), microglia (IBA1), neurons (NeuN), blood vessels (CD31), and tumor cells (H3K27M). Images were captured using the VS200 whole slide scanner. Automatic cell detection was conducted using QuPath, and statistical analysis was performed in GraphPad Prism. RESULTS From initial primary tumor IHC analysis, microglia appear to be present in slightly higher ratios than astrocytes (0.203 vs. 0.148, fraction of total cells, p=0.062). Furthermore, neurons appear in lower numbers compared to microglia and astrocytes (0.036 vs. 0.203 and 0.148, fraction of total cells, p&amp;lt; 0.0001). There are relatively few blood vessels when adjusted for total area (0.084% of total area). In addition, within a single patient, we anticipate fewer microglia and astrocytes in normal tissue and metastatic tissue compared to the primary site. We also anticipate more neurons in normal tissue and metastatic tissue compared to the primary site. FUTURE DIRECTIONS Using this tumor composition data, we plan to create a 3D gel in vitro cell culture model of DMG. In collaboration with individuals at Children’s National and Columbia, we will use this model in conjunction with focused ultrasound and drug testing.
DDDR-08. DISCOVERY OF ER STRESS-INDUCING COMPOUNDS FOR GBM: A PROMISING APPROACH TOWARDS THERAPEUTIC DEVELOPMENT
Authors: Eduardo Veliz, Lorenzo Sansalone, Amanda Maldonado, Roger Leblanc, Vanni Steven, Regina Graham
Journal: Neuro-Oncology (2023)

Abstract The unfolded protein response (UPR) is a pro-survival mechanism triggered by cellular stresses encountered by tumor cells, such as hypoxia, acidosis, reactive oxygen species and even radiation and chemotherapy. In response to increased unfolded or mis-folded proteins in the endoplasmic reticulum (ER), the UPR initiates specific cell signaling pathways aiming to alleviate ER stress and restore ER proteostasis which include increasing the expression of chaperones to aid in protein folding, enhancing protein degradation and reducing global protein synthesis. However, if homeostasis cannot be restored, the UPR switches from survival to cell death. The UPR is a relatively novel therapeutic target for glioblastoma (GBM), and specifically GBM stem-like cells (GSCs) which maintain tumor heterogeneity, drive GBM tumor growth and therapy resistance. Here we tested a series of curcumin derivatives against three GSC lines and identified a trimethoxy bis-chalcone which promotes robust GSC death with an average IC50 of just below 300 nM, a 100-fold increase in activity compared to curcumin. Furthermore, this bis-chalcone was non-toxic to normal human mesenchymal stem cells. Western blot analysis indicated that the bis-chalcone induced robust activation of UPR pro-death protein C/EBP Homologous Protein (CHOP) while simultaneously decreasing the expression of pro-survival chaperone GRP78/Bip. Lastly our bis-chalcone induced caspase 7 expression and PARP cleavage indicating apoptosis. Most ER stress inducing agents promote both the survival, upregulation of Grp78, and cell death arms of the UPR. Here we identified a compound that only promotes UPR cell death signaling and is highly toxic to radiation and temozolomide resistant GSCs while demonstrating no toxicity to non-tumor cells. This is a promising lead compound for the development of UPR targeted GSC/GBM therapeutics.
STEM-19. POTENTIAL THERAPEUTIC EFFECTS OF NOVEL HISTONE DEACETYLASE INHIBITORS ON HUMAN-DERIVED GLIOBLASTOMA TUMORSPHERES
Authors: Seonah Choi, Seo Jin Kim, Junseong Park, Ran Joo Choi, Ju Hyung Moon, Eui-Hyun Kim, Wan-Yee Teo, Jong Hee Chang, Raok Jeon, Seok-Gu Kang
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Histone deacetylase (HDAC) inhibitor is a promising anticancer drug targeting epigenetic alterations on tumor cells, however, failed to prove its feasibility on glioblastoma (GBM) in several trials. We developed new HDAC inhibitors and applied them to human-derived GBM tumorsphere(TS)s to confirm its therapeutic efficacy to overcome the current limitations. Materials and METHODS The expression level of HDAC in GBM versus normal brain tissue was evaluated with RNA sequencing and its knock-down effects were evaluated through western blot, WST, and luciferase assay. The most potential drugs were selected among the candidates through dose-escalation WST assays, and their capacities on HDAC were evaluated through western blot and HDAC activity/inhibition direct assay. The results of the sphere-formation assay, 3D matrix invasion assay, and transcriptome data analysis were compared between the drugs, and bioluminescence images and Kaplain-Meier survival cure were obtained through a mouse model. RESULTS HDAC 8 is more expressed in GBM tissue and TSs than normal ones, and the knock-down of HDAC 8 shows decreases in viability, ATP levels, and related proteins. Two potential HDAC 8 inhibitors were selected and compared with suberoylanilide hydroxamic acid (SAHA) through the experiment, which discovered that they not only reduced HDAC’s expression and its activity but also stemness and invasiveness of GBM TSs to comparable levels despite the differences in transcriptional profile changes, with meaningful survival rates in a mouse model. CONCLUSION We have newly developed meaningful HDAC inhibitors in the tumorsphere stage, and believe it could be a fundamental result for improving future treatment methods.
DDEL-14. EXPLORING THE ROLE OF WNT PATHWAY INHIBITION ON GLIOMA STEM CELLS PROGRESSION AND BRAIN ENDOTHELIAL INTEGRITY
Authors: Kayen Tang, Jeonghan Kang, Christina Conrad, Sanghee Lim, Minhye Kwak, Melissa Cesaire, Sadhana Jackson
Journal: Neuro-Oncology (2023)

Abstract The blood–brain barrier (BBB) is a specialized neurovascular unit evolved to maintain brain homeostasis and prevent effective agents from reaching malignant brain tumors such as glioblastoma. The Wnt/β-catenin signaling pathway helps to ensure BBB integrity and previous studies demonstrate Wnt pathway inhibition increases BBB permeability. High grade gliomas express increased Wnt expression compared with normal tissue. We hypothesize that Wnt pathway inhibition in glioma stem cells (GSCs) will hinder progression, increase BBB permeability, and enhance overall treatment response. In this study, we transduced primary pediatric-derived glioma stem cells with lentiviral vectors overexpressing Wnt inhibitors (DKK1 or WIF1) and then characterized migration, proliferation, and cell cycle progression. WNT inhibition on brain endothelial cell integrity was evaluated with GSC conditioned media (GSC-CM) +/- CHIR99021 (Wnt pathway activator) for function via electrical cell-cell impedance and junctional expression. Wnt inhibitor overexpression was verified using RNAseq, proteomic analysis, and immunoblotting. We found that GSC-DKK1 demonstrated significantly decreased cell migration (p&amp;lt; 0.005) and proliferation (p&amp;lt; 0.0001). We also found that CHIR99021 treated GSC-CM endothelial cells displayed decreased tight junctional proteins and increased fenestration protein expression (p&amp;lt; 0.0005), correlating with a more porous endothelium. Overall, our studies showed Wnt inhibitor overexpressing GSCs impaired glioma progression in vitro and indirectly disrupted endothelial cell integrity. Future studies will evaluate orthotopic Wnt inhibitor overexpressing transplant rodent models to assess changes in BBB integrity, drug permeability, model survival, and treatment response. Further understanding of the Wnt pathway in both GSCs and the BBB has the potential for improved central nervous system treatment penetration and prolonged disease response.
IMMU-36. PD-1KO HEMATOPOIETIC STEM CELLS RAPIDLY DIFFERENTIATE INTO GLIOMA-INFILTRATING EFFECTOR T-CELLS
Authors: Connor Francis, Bayli DiVita Dean, Laura Falceto Font, John Figg, Kaytora Long-James, Alexandra Reid, Dan Jin, David Hilferty, Ginger Moore, Duane Mitchell, Catherine Flores
Journal: Neuro-Oncology (2023)

Abstract INTRODUCTION We previously published that hematopoietic stem cell combination therapy (HSC+aPD1) extends survival in murine CNS malignancies, including glioma. To better understand lymphoid-specific mechanisms, we analyzed various lymphoid tissues in a murine glioma model. We hypothesize early PD-1 blockade in HSCs influences later differentiation trajectories. Transferred HSCs differentiate into T-cells within the thymus and then migrate to the intracranial tumor microenvironment as anticipated. Indeed, blocking PD-1/PD-L1 signaling during HSC differentiation significantly impacts subsequent T-cell maturation. Remarkably, TILs derived from HSCPD1KO cells were biased towards CD4+ Treg or CD8+ effector lineages, whereas HSCPD1+/+ progeny leaned toward immature/naïve cell states. METHODS HSCs were prepared from constitutive GFP-expressing (CD45.2+) and PD1KO (CD45.2+) mice and transferred into CD45.1+ hosts. Sublethal 5Gy total body irradiation was administered day 5 post-intracranial tumor implantation. The next day, 1e6 HSCs from a 1:1-GFP:PD1KO cocktail were injected intravenously. Descriptive statistics are reported as mean ± SD. Transferred HSCs engraft, expand, differentiate, tended and migrate to form approximately 25% of the TIL compartment in only 15 days. RESULTS We found that, 56.2% ± 20.3 of CD3+ TILs display an immature CD4+CD8+ (DP) phenotype in early disease, and 43.8% ± 17.4 of these DP-TILs are HSC-derived. DP-TILs were virtually absent in advanced disease 29 days after treatment, but HSC-derived TILs most commonly fell within the single-positive (SP) TIL subsets, comprising 9.8% ± 5.6 of SP-CD8+ TILs. Notably, HSCPD1KO-derived cells were 4x more abundant amongst SP-CD8 TILs when compared to HSCGFP-derived cells (6.5% vs 1.6%, p &amp;lt; 0.05). SP-CD8 thymocytes were similarly enriched for HSCPD1KO progeny (41.1% vs 24.7%, p &amp;lt; 0.05) suggesting that PD-1 blockade impacts thymopoiesis directly. CONCLUSION PD-1 signaling modulates thymic output. Blocking the PD-1/PD-L1 axis during thymopoiesis increases the abundance of HSC-derived CD8+ effectors at the tumor site. HSC+aPD1 therapy is uniquely positioned to leverage thymus-dependent anti-tumor immunity.
CTNI-41. PHASE II AND PHASE 0 RESULTS OF ABTC 1801: A MULTI-ARM CLINICAL TRIAL OF THE PARP INHIBITOR PAMIPARIB WITH VERY LOW DOSE METRONOMIC TEMOZOLOMIDE IN RECURRENT IDH MUTANT GLIOMAS
Authors: David Schiff, Ranjit S Bindra, Jing Li, Xiaobu Ye, Benjamin Ellingson, Tobias Walbert, Jian Campian, Burt Nabors, Frank Lieberman, Byram Ozer, Arati Desai, Antonio Omuro, Patrick Wen, Serena Desideri, Neeraja Danda, Stuart Grossman
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Preclinical studies have demonstrated that IDH1-mutant (IDHmt) gliomas harbor a BRCAness phenotype with a defect in homologous recombination that confers PARP inhibitor sensitivity. METHODS The phase II component of ABTC 1801 examined the efficacy of the combination of pamiparib (BeiGene BGB-290) with low dose metronomic temozolomide in recurrent IDHmt grade 2 and 3 gliomas. In this two-stage design, Arm A enrolled patients who had failed two lines and Arm B a single line of alkylator therapy. Pamiparib and temozolomide doses based on phase I results was 60 mg BID and 20 mg daily. Primary endpoint was objective response rate (ORR). RESULTS 39 patients (Arm A 15, Arm B 24) enrolled in the phase II. Median age was 45 (range: 25-69), 56% male, and median KPS 90. 72% of tumors were MGMT methylated. There were no confirmed responses in Arm A and one in Arm B; neither arm met the threshold for additional accrual. One-third of subjects discontinued treatment for reasons other than progressive disease. Estimated median PFS was 5.8 months in Arm A and 11.3 months in Arm B. Seven subjects (Arm A 3, Arm B 4) developed DLT during treatment. Grade 3+ toxicity was principally hematologic; 9 patients had grade 3 anemia, 7 grade 3 and 3 grade 4 neutropenia, and 3 grade 3 thrombocytopenia. In enhancing and non-enhancing tumors from 8 surgical arm patients, median unbound drug tumor/plasma ratios were 0.98 and 0.92, respectively; and median unbound pamiparib tumor concentrations were 209 and 188 nmol/L (or nmol/kg), respectively, which were &amp;gt;20-fold the in vitro IC50 for PARP inhibition. CONCLUSIONS While pamiparib appeared to achieve sufficient pharmacologically active concentrations in both enhancing and non-enhancing tumors, combination with temozolomide did not produce a meaningful ORR in IDHmt recurrent gliomas. Cumulative hematologic toxicity was substantial.
EXTH-50. ACUTE AND LONG-TERM RESPONSES TO QUISINOSTAT TREATMENT IN PDX MODELS OF GLIOBLASTOMA
Authors: Keely Orndorff, James McNamara, Costanza LoCascio, Connor White, Mariya Stavnichuk, Kamal Shaik, Tigran Margaryan, Artak Tovmasyan, Nader Sanai, Shwetal Mehta
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Histone deacetylase inhibitors (HDACi) promote reactive oxygen species production, result in DNA damage, and trigger cell fate changes. Quisinostat is a Class I-II selective HDAC inhibitor with high specificity for HDAC1. Here, we evaluated acute and long-term quisinostat treated glioblastoma (GBM) PDX tissues and glioma stem cells for increase in reactive oxygen species and cell fate change. METHODS GBM PDX models (n = 6) and multiple PDX-derived glioma stem cells were treated with quisinostat, radiation, or a combination of quisinostat and radiation. Tissue and cells were processed via LC-MS/MS, RNA-seq, qRT-PCR, immunoblotting, and immunocytochemistry assays to examine increase in cellular reactive oxygen species, oxidative stress biomarkers, and markers of stemness and differentiation. RESULTS RNA sequencing of tumor tissue revealed that chronic co-treatment with quisinostat and radiation led to increased cellular expression of oxidative stress- and neuronal-related genes compared to control group. Immunoblotting confirmed upregulation of neuronal signaling proteins in the quisinostat treated tumor tissue in vivo. qRT-PCR and LC-MS/MS analysis demonstrated an increase in oxidative stress biomarkers following acute quisinostat treatment in vitro. CONCLUSIONS Treatment with quisinostat increased the expression of genes involved in promoting oxidative stress and neuronal signaling in vivo. LC-MS/MS, qRT-PCR, immunoblotting and immunocytochemistry assays confirmed increase in oxidative stress and neuronal markers upon acute treatment in vitro. Cancer cells often express higher levels of reactive oxygen species compared to normal tissue, and oxidative stress is linked to greater survival and proliferation of cancer cells. However, there is much interest in increasing oxidative stress in glioma cells to induce selective cell death in cancer cells. Ongoing studies are aimed at evaluating the significance of these cellular and molecular changes resulting from quisinostat treatment and whether the quisinostat-induced oxidative stress and cell fate changes can be exploited for future combination therapy for GBM.
IMMU-27. NON-TUMOR CELL IDO1 NON-ENZYMATICALLY DECREASES RT + PD-1 MAB TREATMENT EFFICACY IN OLDER ADULTS WITH GLIOBLASTOMA
Authors: Lijie Zhai, April Bell, Evridiki Asimakidou, Kristen Lauing, Miri Kim, Prashant Bommi, Kevin Barton, Ewa Borys, Douglas Anderson, Vikram Prabhu, Theresa Walunas, Gary Schiltz, Jacob Allen, Robert McCusker, Jigisha Thakkar, Rimas Lukas, Derek Wainwright
Journal: Neuro-Oncology (2023)

Abstract Checkmate 498 is a large, randomized, phase 3 clinical trial that demonstrated an improved hazard ratio for younger but not older adults with MGMT unmethylated GBM treated with RT + PD-1 mAb. In an effort to better understand the biological determinant, indoleamine 2,3 dioxygenase 1 (IDO1), and its relationship with reducing RT + PD-1 mAb treatment efficacy in older adults with GBM, we created and/or compared 20-26 month-old C57BL/6 background mice that were IDO1-T2A-GFP [wild-type (WT); negative control (n=16)], IDO1 enzyme null [with normal IDO1 expression potential but incapable of tryptophan metabolism (n=16)], IDO1KO (n=4), Ido1fl/fl (n=14), Lysm-Cre+→Ido1fl/fl [IDO1-deficient in monocytes, macrophages, and microglia (n=20)], CD11c-Cre+→Ido1fl/fl [IDO1-deficient in dendritic cells (n=23)], Tie2-Cre+→Ido1fl/fl [IDO1-deficient in endothelial cells (n=14)]. Mice were intracranially (ic.) engrafted with 5×103 syngeneic GL261 followed by treatment with radiation (RT) + PD-1 mAb beginning at 14-days post ic. IDO1 WT and IDO1 enzyme null mice had a survival rate of 12.5% and 18.75% at 90-day post ic., respectively, which was significantly reduced as compared to IDO1KO mice with a 75% survival rate (p&amp;lt; 0.05). Tie2-Cre+→Ido1fl/fl mice, CD11c-Cre+→Ido1fl/fl, and Lysm-Cre+→Ido1fl/fl mice had a 100%, 96%, and 70% survival rate at 90-day post ic., respectively, as compared to Ido1fl/fl mice with a 42% survival rate (p&amp;lt; 0.05). Significantly reduced kynurenine (KYN) levels were found in IDO1 enzyme null and IDO1KO mice as compared to WT mice (p&amp;lt; 0.001). Unexpectedly, kynurenine levels were also reduced in Tie2-Cre+→Ido1fl/fl but not in CD11c-Cre+→Ido1fl/fl, Lysm-Cre+→Ido1fl/fl or Ido1fl/fl mice (p&amp;lt; 0.05). Tryptophan (TRP) levels did not change between mouse groups. These data support the hypothesis that non-tumor cell IDO1 reduces immunotherapeutic efficacy in older adults with GBM through a TRP-KYN pathway-independent mechanism.
RADT-08. IS THERE A CORRELATION BETWEEN ANEMIA AND RADIATION NECROSIS IN BREAST CANCER PATIENTS WITH BRAIN METASTASES UNDERGOING RADIOSURGERY? A PRELIMINARY SINGLE-INSTITUTION COHORT STUDY
Authors: Hannah Wilding, Leonardo Jose Monteiro De Macedo Filho, Debarati Bhanja, Rabab Husain, Jinpyo Hong, Camille Moeckel, Alireza Mansouri
Journal: Neuro-Oncology (2023)

Abstract INTRODUCTION Stereotactic radiosurgery (SRS) is a highly effective treatment for brain metastases. Radiation necrosis (RN) is a prominent dose-limiting toxicity, occurring in 5-10% of patients. Data on differences in RN incidence based on tumor molecular markers and the potential correlation with anemia have not been explored. The objective of this study was to 1) report our institutional rates of RN in patients with breast cancer brain metastases (BCBM) undergoing radiosurgery; and 2) investigate the correlation of anemia with RN rates. METHODS A retrospective review of patients with BCBM treated with SRS between May 2006 and October 2020 was conducted. To ensure homogeneity, only patients with oligometastatic disease (1-4 BM) and only 1 session of SRS were included. Hemoglobin (Hb) was assessed from 3 months before or 6 months post SRS, and diagnosis of anemia was made for Hb &amp;lt;13 g/dL in males and Hb &amp;lt;12 g/dL in females. Logistic regression was used to analyze correlation of anemia and RN. RESULTS 44 patients were included (82 total lesions treated by SRS, median 2). Seventy-seven lesions were treated with SRS to a median dose of 20 Gy (15-24 Gy). Five lesions were treated with fractionated SRS (30Gy, 3-5 fractions). Five patients (11.4%) developed RN based on imaging; two went on to biopsy with one having pathological confirmation of RN. Anemia was identified in twenty-eight (63.7%) patients; 1 was treated with iron supplementation. Although anemia was not significantly associated with RN, patients with anemia did have significantly lower OS than those without (p = 0.04). CONCLUSION Our institutional data suggest similar RN rates in BCBM patients as the literature. Our sample size was too small to investigate correlation between anemia and RN, though survival may be impacted. Larger, multi-institutional studies are underway to further study this possibility.
DDDR-29. TARGETING FGFR FUSIONS: A CASE OF CATEQUENTINIB (AL3818) AND TEMOZOLOMIDE COMBINATION THERAPY FOR RECURRENT MGMT METHYLATED TACC-FGFR FUSION POSITIVE GLIOBLASTOMA
Authors: Andreas Seas, Mallika Patel, Martin Kowalsky, Daniel S Rudd, Susanne D Jacobs, Elizabeth S Miller, Gena H Volas-Redd, Margaret O Johnson
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND There is no gold-standard for the management of recurrent glioblastoma (GBM). However, advances at the interface of molecular testing and rational drug design have opened avenues for personalized medicine. Here we describe the case of a 52-year-old patient with recurrent GBM (WHO grade 4) with known FGFR3-TACC3 fusion and MGMT promoter methylation by Caris molecular profiling. Initial treatment included radiotherapy with concomitant and adjuvant temozolomide. However, after 18 months off therapy, the patient became clinically and radiographically progressive with multifocal disease. Herein, we describe our experience with temozolomide and catequentinib (AL3818) in a single patient. METHODS We reviewed the available literature on targeting FGFR3-TACC3 fusion positive glioblastoma with catequentinib (1-[[[4-(4-fluoro-2-methyl-1H-indol-5-yloxy)-6-methoxyquinolin-7-Yl] oxy] methyl] cyclopropanamine dihydrochloride). Catequentinib is an oral small-molecule pan-kinase inhibitor with selective VEGFR2 inhibition, it is under investigation in multiple phase 2 and 3 clinical trials and can safely be administered concomitantly with temozolomide. We obtained single-patient Investigational New Drug (IND) approval and free drug was shipped directly from the manufacturer (Advenchen Laboratories; Jiangsu Chia-Tai Tianqing Pharmaceutical) to our institution’s investigational chemotherapy pharmacy. We administered catequentinib 12 mg by mouth for 14 days on and 7 days off of a 21-day cycle along with temozolomide 50mg/m2/day of a 28-day cycle with routine monitoring of laboratory parameters. RESULTS The combination of temozolomide and catequentinib was well-tolerated, resulted in clinical stability, and partial radiographic response at 3-month follow-up. CONCLUSION Catequentinib in combination with metronomic temozolomide was well tolerated in this single patient. This patient’s response shows the promise of intentional, patient-specific care at the intersection of molecular testing and rational drug design. The patient will continue therapy and updated clinical and radiographic outcomes will be presented.